Attachment Methods for Surface Features of Wind Turbine Rotor Blades

ABSTRACT

The present disclosure is directed to methods for attaching a plurality of surface features to a rotor blade of a wind turbine. Such methods may include direct molding of the surface features to the rotor blade, bonding arrays of connected components to the rotor blade and subsequently removing connections between components, as well as using a flexible template with or without a tinted adhesive.

RELATED APPLICATIONS

The present disclosure claims priority to and is a divisionalapplication of U.S. Ser. No. 15/292,262 filed on Oct. 13, 2016, which isincorporated herein by references in its entirety.

FIELD OF THE INVENTION

The present disclosure relates in general to wind turbine rotor blades,and more particularly to attachment methods for surface features forwind turbine rotor blades.

BACKGROUND OF THE INVENTION

Wind power is considered one of the cleanest, most environmentallyfriendly energy sources presently available, and wind turbines havegained increased attention in this regard. A modern wind turbinetypically includes a tower, a generator, a gearbox, a nacelle, and oneor more rotor blades. The rotor blades capture kinetic energy of windusing known foil principles. The rotor blades transmit the kineticenergy in the form of rotational energy so as to turn a shaft couplingthe rotor blades to a gearbox, or if a gearbox is not used, directly tothe generator. The generator then converts the mechanical energy toelectrical energy that may be deployed to a utility grid.

In many cases, accessory components are attached to the rotor blades ofwind turbines to perform various functions during operation of the windturbine. For example, it is known to change the aerodynamiccharacteristics of wind turbine rotor blades by adding protrusions orother structures (often referred to as “vortex generators”) to thesurface of the blade in order to increase the energy conversionefficiency during normal operation of the wind turbine by increasing thelift force of the blades while decreasing the drag force. Vortexgenerators serve to increase the attached-flow region and to reduce thedetached-flow region by moving flow separation nearer the trailing edgeof the blade. In particular, vortex generators create local regions ofturbulent airflow over the surface of the blade as a means to prolongflow separation and thus optimize aerodynamic airflow around the bladecontour. Conventional vortex generators are defined as “fins” or shapedstructures on the suction side of the turbine blade. More specifically,many vortex generators include a flange portion with the fin extendingtherefrom. Further surface features may also include boundary layerenergizers that are commonly used to reduce the effect of a stall or ahigh angle of attack.

The curvature of the blade surface that such surface features attach tochanges, which may require custom tooling and parts to fit everyindividual location on the rotor blade. Further, many surface featuresdefine a “step” at an interface between a flange portion thereof and thesurface of the rotor blade. In addition, installation techniques andsystems for attaching conventional surface features can be quiteexpensive and time consuming, particularly for field installations. Forexample, typical field installation techniques require the use ofattachment fixtures and significant dwell time for curing the attachmentadhesives. The adhesives typically are considered hazardous materialsand appropriate precautions and protective measures (both equipment andpersonal) must be taken. Further, for particularly small surfacefeatures, locating a plurality of such features on a blade surface canbe time consuming and tedious.

Thus, improved methods for attaching such surface features to windturbine rotor blades would be welcomed in the art.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one aspect, the present disclosure is directed to a method forforming and attaching a plurality of surface features onto a rotor bladeof a wind turbine. The method includes locating a mold of the pluralityof surface features at a desired location on either of a suction side ora pressure side of the rotor blade. Further, the mold forms a pluralityof cavities with either of the suction side or the pressure side of therotor blade when mounted thereto. As such, the method also includesfilling the plurality of cavities with one or more materials so as toform the plurality of surface features thereon. In addition, the methodincludes curing and attaching the plurality of surface features so as toadhere to either of the suction side or the pressure side of the rotorblade. Moreover, the method includes removing the mold from either ofthe suction side or the pressure side of the rotor blade.

In one embodiment, each of the cavities includes at least one opening.In such embodiments, the step of filling the plurality of cavities withthe one or more materials so as to form the plurality of surfacefeatures may include separately placing the one or more materials intoeach of the openings. In certain embodiments, the one or more materialsmay include a thermoset material, a thermoplastic material, rubber, areinforcement material, a putty, or combinations thereof. Morespecifically, the material(s) may include any compound of two or moreliquid- and/or putty-based thermoset compounds. In addition, the one ormore materials may include one or more fillers (such as glass fiber). Ina particular embodiment, for example, the material may be epoxy.Further, the reinforcement material(s) may comprise one or more fibermaterials including but not limited to glass fibers, carbon fibers,polymer fibers, ceramic fibers, nanofibers, metal fibers, or similar.

In another embodiment, the method may include applying pressure to themold after filling the plurality of cavities with the one or morematerials so as to squeeze out excess one or more materials and removingthe excess one or more materials before curing the plurality of surfacefeatures. Alternatively, the method may include applying pressure to themold before and/or during filling of the plurality of cavities so as toprevent excess material from squeezing out of the cavities.

In alternative embodiments, the step of filling the plurality ofcavities with the one or more materials so as to form the plurality ofsurface features may include injecting the one or more materials into afirst side of the mold via at least one of vacuum infusion or pressureinjection and allowing the one or more materials to flow into each ofthe plurality of cavities.

In additional embodiments, the method may include removing excess curedmaterial, e.g. between the cured surface features.

In yet another embodiment, the mold may be constructed of a flexiblematerial. For example, in certain embodiments, the flexible material ofthe mold may include rubber, silicone, or combinations thereof.

In another aspect, the present disclosure is directed to a method forattaching a plurality of surface features to a rotor blade of a windturbine. The method includes forming a single blade add-on componentcontaining the plurality of surface features connected to each other viaa removable connector. Further, the single blade add-on component mayinclude a curvature that corresponds to a curvature of the rotor blade.As such, the method further includes locating the single blade add-oncomponent at a desired location on either of the suction side or thepressure side of the rotor blade. The method also includes applying anattachment layer between a blade-side surface of each of the pluralityof surface features and either of the suction side or the pressure side.In addition, the method includes securing the single blade add-oncomponent at the desired location.

In one embodiment, the method includes forming the single blade add-oncomponent containing the surface features from a thermoset material. Inanother embodiment, the method may include forming the single bladeadd-on component via at least one of injection molding,three-dimensional (3D) printing, vacuum infusion, thermoforming, vacuumforming, or any other suitable manufacturing method.

In further embodiments, the step of securing the single blade add-oncomponent at the desired location may further include applying pressureto each of the surface features so as to allow the attachment layer(s)to bond to the rotor blade.

In additional embodiments, the method may include removing one or moreof the removable connectors from between the plurality of surfacefeatures after securing the single blade add-on component at the desiredlocation.

In yet another embodiment, the attachment layer may include double-sidetape having an inner acrylic foam layer disposed between a first outeradhesive layer and a second outer adhesive layer. As such, in certainembodiments, the step of applying the attachment layer between theblade-side surface of each of the plurality of surface features andeither of the suction side or the pressure side may include cutting apredetermined pattern into the double-sided tape through the first andsecond outer adhesive layers, a first liner cover adjacent to the firstouter adhesive layer, and a second liner cover adjacent to the secondouter adhesive layer, selectively removing cut portions of the firstliner cover and the second liner cover corresponding to thepredetermined pattern to expose portions of the first and second outeradhesive layers, securing the exposed portions of the second outeradhesive layer to either of the suction side or the pressure side,wherein the exposed portions of the first outer adhesive layer arelocated at the desired location, and removing remaining portions of thefirst and second outer adhesive liners and the first and second linercovers.

In yet another aspect, the present disclosure is directed to a methodfor attaching a plurality of surface features to a rotor blade of a windturbine. The method includes locating a flexible template at a desiredlocation on either of a suction side or a pressure side of the rotorblade. Further, the flexible template has a plurality of hole locations,with each hole location corresponding to an attachment location for oneof the surface features. The method also includes applying a firstattachment feature around an outer periphery of each of the holelocations. Further, the method includes applying a second attachmentfeature within the first attachment feature, the second attachmentfeature being spaced from the first attachment feature in a center ofthe hole location. In addition, the method includes removing theflexible template from the rotor blade and securing at least one of theplurality of surface features at each of the attachment locations viathe first and second attachment features.

In one embodiment, the first and second attachment features may includean adhesive or a double-side tape. In certain embodiments, thedouble-side tape includes an inner acrylic foam layer disposed between afirst outer adhesive layer and a second outer adhesive layer. In suchembodiments, the first attachment feature may include the double-sidedtape, whereas the second attachment feature may include the adhesive orvice versa.

Alternatively, in further embodiments, the first attachment feature mayinclude a tinted adhesive. In such embodiments, the step of applying thefirst attachment feature may include spraying the tinted adhesive ateach of the hole locations and securing at least one of the plurality ofsurface features at each of the attachment locations marked by thetinted adhesive.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 illustrates a perspective view of one embodiment of a windturbine according to the present disclosure;

FIG. 2 illustrates a perspective view of one embodiment of a rotor bladeassembly according to the present disclosure;

FIG. 3 illustrates a partial top view of another embodiment of a rotorblade assembly according to the present disclosure, particularlyillustrating a plurality of surface features;

FIG. 4 illustrates a flow diagram of one embodiment of a method forattaching a plurality of surface features to a rotor blade according tothe present disclosure;

FIG. 5 illustrates a schematic process flow diagram of one embodiment ofa method for attaching a plurality of surface features to a rotor bladeaccording to the present disclosure;

FIG. 6 illustrates a flow diagram of another embodiment of a method forattaching a plurality of surface features to a rotor blade according tothe present disclosure;

FIG. 7 illustrates a schematic process flow diagram of anotherembodiment of a method for attaching a plurality of surface features toa rotor blade according to the present disclosure;

FIG. 8 illustrates a detailed cross-sectional view of one embodiment ofa surface feature attached to a rotor blade via an attachment layeraccording to the present disclosure;

FIG. 9 illustrates a blade-side surface of one embodiment of a singleblade add-on component according to the present disclosure, particularlyillustrating first and second attachment features configured thereon;

FIG. 10 illustrates a detailed cross-sectional view of one embodiment ofan attachment layer for a surface feature of a rotor blade according tothe present disclosure;

FIG. 11 illustrates a detailed cross-sectional view of the attachmentlayer of FIG. 10 being located on the rotor blade according to thepresent disclosure;

FIG. 12 illustrates a flow diagram of yet another embodiment of a methodfor attaching a plurality of surface features to a rotor blade accordingto the present disclosure;

FIG. 13 illustrates a schematic process flow diagram of yet anotherembodiment of a method for attaching a plurality of surface features toa rotor blade according to the present disclosure; and

FIG. 14 illustrates a schematic process flow diagram of still anotherembodiment of a method for attaching a plurality of surface features toa rotor blade according to the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Referring now to the figures, FIG. 1 illustrates a wind turbine 10 ofconventional construction. The wind turbine 10 includes a tower 12 witha nacelle 14 mounted thereon. A plurality of rotor blades 16 are mountedto a rotor hub 18, which is in turn connected to a main flange thatturns a main rotor shaft (not shown). The wind turbine power generationand control components are housed within the nacelle 14. The view ofFIG. 1 is provided for illustrative purposes only to place the presentinvention in an exemplary field of use. It should be appreciated thatthe invention is not limited to any particular type of wind turbineconfiguration.

Referring to FIG. 2, a rotor blade assembly 100 in accordance withaspects of the invention is illustrated. As shown, the rotor bladeassembly 100 includes a rotor blade 16 having surfaces defining pressureand suction sides 22, 24 extending between a leading edge 26 and atrailing edge 28. Further, the rotor blade 16 may extend from a bladetip 32 to a blade root 34. The surfaces defining the pressure side 22,the suction side 24, the leading edge 26, and the trailing edge 28further define a rotor blade interior or cavity. Further, the rotorblade 16 defines a chord 42 and a span 44. As shown, the chord 42 mayvary throughout the span 44 of the rotor blade 16. Thus, a local chordmay be defined for the rotor blade 16 at any point on the rotor blade 16along the span 44.

In some embodiments, the rotor blade 16 may include a plurality ofindividual blade segments aligned in an end-to-end order from the bladetip 32 to the blade root 34. Each of the individual blade segments maybe uniquely configured so that the plurality of blade segments define acomplete rotor blade 16 having a designed aerodynamic profile, length,and other desired characteristics. For example, each of the bladesegments may have an aerodynamic profile that corresponds to theaerodynamic profile of adjacent blade segments. Thus, the aerodynamicprofiles of the blade segments may form a continuous aerodynamic profileof the rotor blade 16. Alternatively, the rotor blade 16 may be formedas a singular, unitary blade having the designed aerodynamic profile,length, and other desired characteristics.

In further embodiments, the rotor blade 16 may be curved. Curving of therotor blade 16 may entail bending the rotor blade 16 in a generallyflap-wise direction and/or in a generally edgewise direction. Theflap-wise direction may generally be construed as the direction (or theopposite direction) in which the aerodynamic lift acts on the rotorblade 16. The edgewise direction is generally perpendicular to theflap-wise direction. Flap-wise curvature of the rotor blade 16 is alsoknown as pre-bend, while edgewise curvature is also known as sweep.Thus, a curved rotor blade 16 may be pre-bent and/or swept. Curving mayenable the rotor blade 16 to better withstand flap-wise and edgewiseloads during operation of the wind turbine 10, and may further provideclearance for the rotor blade 16 from the tower 12 during operation ofthe wind turbine 10.

Still referring to FIG. 2, the rotor blade 16 defines a pitch axis 40relative to the rotor hub 18. For example, the pitch axis 40 may extendgenerally perpendicularly to the rotor hub 18 and blade root 34 throughthe center of the blade root 34. A pitch angle or blade pitch of therotor blade 16, i.e., an angle that determines a perspective of therotor blade 16 with respect to the air flow past the wind turbine 10,may be defined by rotation of the rotor blade 16 about the pitch axis40.

FIG. 2 further depicts a plurality of surface features 102 located onthe suction side 24 of the rotor blade 16 along the span 44 thereof.More specifically, in the illustrated embodiment, the surface features102 are configured in pairs to define generally V-shaped formationsoriented towards the leading edge 26 of the rotor blade 16. In furtherembodiments, the surface features 102 may be arranged in any suitableformation in addition to the V-shaped formation.

Further, it should be understood that the surface features 102 aredepicted on the suction side surface 24 of the blade 16 for illustrativepurposes only and may also be provided on the pressure side surface 22.For example, in additional embodiments, the surface features 102 may beplaced at any location on either or both of the flow surfaces 22, 24 ofthe rotor blade 16 wherein it is desired to modify the aerodynamiccharacteristics of the surface. In a particular embodiment, the surfacefeatures 102 may each have different sizes and/or configurationsdepending on their span-wise location on the rotor blade 16. Moreover,as shown in FIG. 2, there are three groupings of surface features 102,with the grouping closest to the blade root 34 being larger (or havingan overall different shape or configuration) as compared to the adjacentgroupings. In alternate embodiments, all of the surface features 102 maybe disposed closer to a tip portion 32 of the blade 15 as compared to aroot portion 34, or closer to the root portion 34 as compared to the tipportion 32. It should be understood that the invention is not limited toany particular placement of the surface features 102 on either or bothflow surfaces 22, 24 of the blade 16.

It should also be appreciated that the surface features 102 describedherein may have different shape configurations within the scope andspirit of the invention. For example, as shown in FIG. 3, the surfacefeatures 102 of the present disclosure may include vortex generatorshaving a fin-type protrusion configuration that is used for illustrativepurposes only. As such, any type of protrusion serving as a flowdisrupter for improving the aerodynamic efficiency of the rotor blade 16is within the scope of the invention. More specifically, as shown, thesurface features 102 of the present disclosure may include a baseportion 104 and a protrusion member 108 extending upwardly from the baseportion 104. As such, the base portion 104 generally defines a generallycontinuous structure that presents a surface that contours and adheresto the mating blade surface 24, whereas the protrusion member 108generally disrupts the airflow across the blade surface.

Referring now to FIGS. 4-14, the present disclosure is directed tovarious methods for attaching such surface features 102 to the rotorblade 16. More specifically, in certain embodiments, the presentdisclosure is directed to various manufacturing and attachment methodsfor generally small blade add-on features, such as boundary layerenergizers and small vortex generators that are useful for increased AEPapplications and/or other performance gains.

Referring particularly to FIGS. 4 and 5, one embodiment of the presentdisclosure is directed to a method 200 for forming and attaching aplurality of the surface features 102 onto a rotor blade of a windturbine, such as the rotor blade 16 of FIG. 2, via direct molding. Asshown at 202, the method 200 includes locating a mold 106 of theplurality of surface features 102 at a desired location on either of thesuction or pressure sides 22, 24 of the rotor blade 16. For example, asshown in FIG. 5(A), the mold 106 is placed on the suction side 24 of therotor blade 16. Thus, as shown in FIG. 5(B), the mold 106 forms one ormore cavities 118 with the suction side 24 of the rotor blade 16 whenmounted thereto. As described herein, the mold 106 may be constructed ofa flexible material. For example, in certain embodiments, the flexiblematerial of the mold 106 may include any flexible polymer such asrubber, silicone, or combinations thereof. More specifically, in oneembodiment, the mold 106 may be a silicone rubber mold that isrelatively non-stick, thereby providing a mold that is easy to removefrom the cured components. In addition, the mold 106 may be constructedof a transparent material that allows a user to see when the cavities118 are completely filled.

Thus, as shown at 204, the method 200 includes filling the cavities 118of the mold 106 with one or more materials 120 so as to form theplurality of surface features 102. More specifically, as shown in FIG.5(C), the step of filling the cavities 118 with the one or morematerials 120 may include placing (e.g. by injecting) the one or morematerials 120 into a first side of the mold 106. For example, in certainembodiments, the one or more materials 120 may be injected into thecavities 118 of the mold 106 via at least one of vacuum infusion orpressure injection. In such embodiments, as shown, the material(s) 120(e.g. a resin material) is allowed to flow into each of the plurality ofcavities 118 from the injection point. In alternative embodiments, asshown in FIG. 5(D), each of the cavities 118 may include at least oneopening 122. In such embodiments, the step of filling the cavities 118with the one or more materials 120 may include separately placing theone or more materials 120 into each of the openings 122. In anotherembodiment, as shown in FIGS. 5(E) and 5(F), the method 200 may alsoinclude applying pressure to the mold 106 after filling the cavities 118with the one or more materials 120 so as to squeeze out excess material124.

In certain embodiments, the one or more materials 120 may include athermoset material, a thermoplastic material, rubber, a reinforcementmaterial, a putty, or combinations thereof. More specifically, the oneor more materials 120 may include a fast-setting thermoset material. Thethermoset materials as described herein generally encompass a plasticmaterial or polymer that is non-reversible in nature. For example,thermoset materials, once cured, cannot be easily remolded or returnedto a liquid state. As such, after initial forming, thermoset materialsare generally resistant to heat, corrosion, and/or creep. Examplethermoset materials may generally include, but are not limited to, somepolyesters, some polyurethanes, esters, epoxies, or any other suitablethermoset material. More specifically, the material(s) 120 may includeany compound of two or more liquid- and/or putty-based thermosetcompounds. In addition, the material(s) 120 may include one or morefillers (such as glass fiber).

The thermoplastic materials as described herein generally encompass aplastic material or polymer that is reversible in nature. For example,thermoplastic materials typically become pliable or moldable when heatedto a certain temperature and return to a more rigid state upon cooling.Further, thermoplastic materials may include amorphous thermoplasticmaterials and/or semi-crystalline thermoplastic materials. For example,some amorphous thermoplastic materials may generally include, but arenot limited to, styrenes, vinyls, cellulosics, polyesters, acrylics,polysulphones, and/or imides. More specifically, exemplary amorphousthermoplastic materials may include polystyrene, acrylonitrile butadienestyrene (ABS), polymethyl methacrylate (PMMA), glycolised polyethyleneterephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphouspolyamide, polyvinyl chlorides (PVC), polyvinylidene chloride,polyurethane, or any other suitable amorphous thermoplastic material. Inaddition, exemplary semi-crystalline thermoplastic materials maygenerally include, but are not limited to polyolefins, polyamides,fluropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and/oracetals. More specifically, exemplary semi-crystalline thermoplasticmaterials may include polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene,polyamide (nylon), polyetherketone, or any other suitablesemi-crystalline thermoplastic material.

Further, the reinforcement material(s) as described herein may generallyencompass one or more fiber materials including but not limited to glassfibers, carbon fibers, polymer fibers, ceramic fibers, nanofibers, metalfibers, or similar.

Referring back to FIG. 4, as shown at 206, the method 200 furtherincludes curing the plurality of surface features 102 such that thefeatures 102 adhere to either of the suction or pressure sides 22, 24 ofthe rotor blade 16. For example, it should be understood that the curingstep creates a bond between the surface features 102 and the rotor blade16. Moreover, as shown at 208, the method 200 includes removing the mold106 from either of the suction or pressure sides 22, 24 of the rotorblade 16 after the surface features 102 have cured. For example, FIG.5(F) illustrates the rotor blade 16 wherein the mold 106 has beenremoved and the surface features 102 are directly molded to the suctionside 24 of the rotor blade 16.

In another embodiment, the method 200 may also include removing theexcess material 124 from the rotor blade 16, i.e. at the edges of themold 106 (FIG. 5(E)) and/or between the surface features 102 (FIG. 5(F))either before or after curing the surface features 102 to the rotorblade 16. More specifically, in certain embodiments, the excess material124 may be removed by hand, via a squeegee, or by any other suitablemeans.

Referring now to FIGS. 6 and 7, another embodiment of the presentdisclosure directed to a method 300 for attaching the surface features102 to the rotor blade 16 is illustrated. As shown at 302, the method300 includes forming a single blade add-on component 126 containing theplurality of surface features 102 connected to each other via aremovable connector 128, e.g. an array of connected parts. Morespecifically, as shown in FIG. 7(A), each of the surface features 102 ofthe blade add-on component 126 are connected together via connectors 128joined by lines of perforation 129. Further, in one embodiment, themethod 300 may include forming the single blade add-on component 126from a thermoset material, such as the thermoset materials describedherein. In another embodiment, the method 300 may include forming thesingle blade add-on component 126 via at least one of injection molding,three-dimensional (3D) printing, thermoforming, vacuum forming, orvacuum infusion.

Further, as shown in FIGS. 7(A) and 7(B), the single blade add-oncomponent 126 may be formed with a curvature 130 that corresponds to acurvature 132 of the rotor blade 16 at one or more locations thereof.Thus, as shown at 304, the method 300 further includes locating thesingle blade add-on component 126 at a desired location on either of thesuction side 24 or the pressure side 22 of the rotor blade 16. Morespecifically, the single blade add-on component 126 may be located at alocation where the curvature 130 of the component 126 generally matchesthe curvature 132 of the rotor blade 16. For example, as shown in FIG.7(B), the single blade add-on component 126 is located on the suctionside 24 of the rotor blade 16 where the curvatures 130, 132substantially match.

As shown at 306, the method 300 also includes applying an attachmentlayer 110 between a blade-side surface of the blade add-on component 126and either of the suction side 24 or the pressure side 22 of the rotorblade 16. For example, as shown in FIGS. 7(C) and 8, the attachmentlayer 110 may be a double-sided adhesive sheet or tape material 112,such as a Very High Bond (VHB)/SAFT (Solar Acrylic Foam Tape) foam-basedtape. Various examples of VHB/SAFT foam-based materials are commerciallyavailable, for example from 3M Corporation of St. Paul, Minn., USA.Further, as shown in FIG. 8, the double-sided tape 112 may have an inneracrylic foam layer 113 disposed between a first outer adhesive layer 114and a second outer adhesive layer 116.

In further embodiments, the attachment layer 110 as described herein maybe applied as a continuous strip between the blade add-on component 126(or any surface feature 102 described herein) and the underlying bladesurface 24 (e.g. as shown in FIG. 7), or may be applied in adiscontinuous pattern. In additional embodiments, as shown in FIG. 9,the attachment layer 110 may include the double-faced adhesive tape 112around the periphery 127 of the blade add-on component 126 or surfacefeature 102 and an adhesive 119 in a center portion thereof. As such,the tape 112 may provide a sealed surface to prevent squeeze out of theadhesive 119 when the surface feature 102 is applied to the bladesurface and/or when adhesive is injected in between the surface feature102 and rotor blade 16. Though the illustrated embodiment depicts theadhesive 119 configured in the center portion of the blade add-oncomponent 126 as generally circular dots, it should be understood thatany configuration of adhesive may be further utilized in additionalembodiments in combination with the double-side tape 112.

Referring now to FIGS. 10 and 11, the step of applying the attachmentlayer 110 between the blade-side surface of blade add-on component 126or surface feature 102 and either of the suction side 24 or the pressureside 22 may include cutting a predetermined pattern 134 (as indicated bythe dotted lines) into a first liner cover 115 of the first outeradhesive layer 114. For example, in certain embodiments, thedouble-sided tape 112 may be die cut or laser cut. Thus, the method 300may further include selectively removing cut portions 136 of the firstliner cover 115 from atop of the first outer adhesive layer 114corresponding to the predetermined pattern 134 to expose portions of thefirst outer adhesive layer 114 (FIG. 11). As such, the predeterminedpattern 134 is configured to set the part location and enable selectiveliner removal and tape removal as desired. The method 300 may alsoinclude removing the second liner cover 117 from the second outeradhesive layer 116 and securing the second outer adhesive layer 116 toeither of the suction side 24 or the pressure side 22 of the rotor blade16. As such, the surface features 102 and/or the blade add-on component126 of the present disclosure can be secured to the exposed portions 138of the first outer adhesive layer 114. In additional embodiments, oncethe tape 112 and surface features 102 have been applied to the blade 16,the method 300 may also include removing the excess tape 112 with theliner(s) still intact. Thus, it should be understood that cutting theattachment layer 110 as described above so as to locate and attach thesurface features 102 on the rotor blade 16 may be completed alone or incombination with any of the additional attachment methods as describedherein.

Referring back to FIG. 6, as shown at 308, the method 300 may alsoinclude securing the single blade add-on component 126 or surfacefeature 102 at the desired location. For example, as shown in FIG. 7(D),the step of securing the single blade add-on component 126 at thedesired location may further include applying pressure to each of theplurality of surface features 102 so as to allow the attachment layers110 to bond to the rotor blade 16.

In additional embodiments, as shown in FIGS. 7(D) and 7(E), the method300 may include removing one or more of the connectors 128 from betweenthe plurality of surface features 102 after securing the single bladeadd-on component 126 at the desired location. For example, in certainembodiments, the connectors 128 may be removed along the lines ofperforation 129. Further, as shown in FIG. 7(E), the method 300 mayinclude removing portions 133 of the attachment layer 110 from betweenthe plurality of surface features 102 either before or after securingthe single blade add-on component 126 at the desired location.

Referring now to FIGS. 12 and 13, yet another embodiment of a method 400for attaching the surface features 102 to the rotor blade 16 isillustrated. As shown at 402 of FIG. 12 and FIG. 13(B), the method 400includes locating a flexible template 140 at a desired location oneither of the suction side 24 or the pressure side 22 of the rotor blade16. More specifically, as shown in FIG. 13(A), the flexible template 140has a plurality of hole locations 142, with each hole location 142corresponding to an attachment location 144 for one of the surfacefeatures 102 as described herein. As shown at 404, the method 400includes applying a first attachment feature 146 (e.g. the double-sidedtape 112) around an outer periphery 150 of each of the hole locations142. As shown at 406, the method 400 includes applying a secondattachment feature 148 (e.g. the adhesive 119) within the firstattachment feature 146. For example, as shown in FIG. 13(C), the firstattachment feature 146 may be placed around the outer periphery 150 ofeach hole location 142, with the second attachment feature 138 spacedfrom the first attachment feature 146 in a center thereof. As shown at408, the method 400 includes removing the flexible template 140 from therotor blade 16. For example, FIG. 13(D) illustrates the first and secondattachment features 146, 148 located on the rotor blade 16 with thetemplate 140 removed therefrom.

Referring still to FIG. 12, as shown at 410, the method 400 includessecuring at least one of the surface features 102 at each of theattachment locations 144 via the first and second attachment features146, 148. For example, as shown in FIGS. 13(D) and (E), the surfacefeatures 102 may first be secured to the rotor blade 16 via thedouble-side tape 112 (i.e. first attachment feature 146) and furthersecured by the adhesive 119 (i.e. second attachment feature 148) as theadhesive cures to the surface features 102.

As mentioned, the step of applying the first and second attachmentfeatures 146, 148 may also include cutting a predetermined pattern intothe first liner cover 115 of the first outer adhesive layer 114,selectively removing cut portions of the first liner cover 115 from thefirst outer adhesive layer 114 corresponding to the predeterminedpattern 134 to expose portions of the first outer adhesive layer 114 forattachment of the plurality of surface features 102, removing a secondliner cover 117 from the second outer adhesive layer 116, and securingthe second outer adhesive layer 116 to the rotor blade 16.

Alternatively, as shown in FIG. 14, the first and/or second attachmentfeatures 146, 148 may correspond to a tinted adhesive 152. For example,in one embodiment, the first attachment feature 146 may correspond to atinted adhesive 152. Thus, as shown, the hole locations 142 may bemarked by spraying the tinted adhesive 152 at each of the hole locations142 and securing at least one of the plurality of surface features 102at each of the attachment locations 144 marked by the tinted adhesive152. More specifically, as shown, the tinted adhesive 152 may cover all(FIG. 14(A)) or a portion (FIG. 14(B)) of each hole location 102. Forexample, as shown in FIG. 14(B), the spray pattern can be such that theadhesive pattern covers only the outer perimeter of each hole location142 and a separate amount of a different adhesive (labeled secondattachment feature 146) can be applied in the center of each holelocation 142 before the surface features 102 are attached thereto. Oncethe attachment locations 144 are marked, as mentioned, the method 400further includes securing at least one of the surface features 102thereto.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method for attaching a plurality of surfacefeatures to a rotor blade of a wind turbine, the method comprising:forming a single blade add-on component comprising the plurality ofsurface features connected to each other via a removable connector, thesingle blade add-on component comprising a curvature that corresponds toa curvature of the rotor blade; locating the single blade add-oncomponent at a desired location on either of the suction side or thepressure side of the rotor blade; applying an attachment layer between ablade-side surface of each of the plurality of surface features andeither of the suction side or the pressure side; and, securing thesingle blade add-on component at the desired location via the attachmentlayer.
 2. The method of claim 1, further comprising forming the singleblade add-on component comprising the plurality of surface features fromat least one of a thermoset material or a thermoplastic material.
 3. Themethod of claim 1, wherein securing the single blade add-on component atthe desired location further comprises applying pressure to each of theplurality of surface features so as to allow the attachment layers tobond to the rotor blade.
 4. The method of claim 1, further comprisingremoving one or more of the removable connectors from between theplurality of surface features after securing the single blade add-oncomponent at the desired location.
 5. The method of claim 1, furthercomprising forming the single blade add-on component via at least one ofinjection molding, three-dimensional (3D) printing, thermoforming,vacuum forming, or vacuum infusion.
 6. The method of claim 1, whereinthe attachment layer comprises double-side tape comprising an inneracrylic foam layer disposed between a first outer adhesive layer and asecond outer adhesive layer.
 7. The method of claim 6, wherein applyingthe attachment layer between the blade-side surface of each of theplurality of surface features and either of the suction side or thepressure side further comprises: cutting a predetermined pattern intothe double-sided tape through the first and second outer adhesivelayers, a first liner cover adjacent to the first outer adhesive layer,and a second liner cover adjacent to the second outer adhesive layer;selectively removing cut portions of the first liner cover and thesecond liner cover corresponding to the predetermined pattern to exposeportions of the first and second outer adhesive layers; securing theexposed portions of the second outer adhesive layer to either of thesuction side or the pressure side, wherein the exposed portions of thefirst outer adhesive layer are located at the desired location; and,removing remaining portions of the first and second outer adhesiveliners and the first and second liner covers.
 8. A method for attachinga plurality of surface features to a rotor blade of a wind turbine, themethod comprising: locating a flexible template at a desired location oneither of a suction side or a pressure side of the rotor blade, theflexible template having a plurality of hole locations, each holelocation corresponding to an attachment location for one of the surfacefeatures; applying a first attachment feature around an outer peripheryof each of the hole locations; applying a second attachment featurewithin the first attachment feature, the second attachment featurespaced from the first attachment feature in a center of the holelocation; removing the flexible template from the rotor blade; and,securing at least one of the plurality of surface features at each ofthe attachment locations via the first and second attachment features.9. The method of claim 8, wherein the first and second attachmentfeatures comprise at least one of an adhesive or a double-side tape, thedouble-side tape comprising an inner acrylic foam layer disposed betweena first outer adhesive layer and a second outer adhesive layer.
 10. Themethod of claim 9, wherein the first attachment feature comprises thedouble-sided tape and the second attachment feature comprises theadhesive.
 11. The method of claim 10, wherein the first attachmentfeature comprises a tinted adhesive, and wherein applying the firstattachment feature around an outer periphery of each of the holelocations further comprises: spraying the tinted adhesive at each of thehole locations; and, securing at least one of the plurality of surfacefeatures at each of the attachment locations marked by the tintedadhesive.